Effects of clonidine on postoperative nausea and vomiting in breast cancer surgery

Background: Postoperative nausea and vomiting (PONV) is still common, especially among female patients. Our hypothesis is that coinduction with clonidine reduces the incidence of PONV in adult patients undergoing breast cancer surgery. Methods: Sixty-eight women premedicated with midazolam were randomly allocated to coinduction with intravenous clonidine (group C) or placebo (group P) in this prospective, double-blind study. Anesthesia was standardized (laryngeal mask airway, fentanyl, propofol, sevoflurane, nitrous oxide, and oxygen). Hemodynamic parameters and the requirements for propofol, sevoflurane, and the postoperative need for ketobemidone were noted. The primary endpoints studied were the number of PONV-free patients and patient satisfaction with respect to PONV. Results: Patients in group C had a significantly reduced need for propofol (P < 0.04) and sevoflurane (P < 0.01) and a reduced early need for ketobemidone (P < 0.04). There were significantly more PONV-free patients in group C compared with group P (20 and 11 of 30, respectively; P < 0.04). The number needed to treat was 3.3 (95% confidence Interval, 1.8, 16.9). Intraoperative blood pressure, postoperative heart rate, and postoperative blood pressure were all significantly lower in group C compared with group P, but were not considered to be of clinical importance. No negative side effects were recorded. Conclusion. Coinduction with clonidine significantly increased the number of PONY-free patients after breast cancer surgery with general anesthesia.